From patchwork Thu Feb 14 20:19:26 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 10813749 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 76944180E for ; Thu, 14 Feb 2019 20:32:07 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 635362EEAC for ; Thu, 14 Feb 2019 20:32:07 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5768B2EEC7; Thu, 14 Feb 2019 20:32:07 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 046EB2EEAC for ; Thu, 14 Feb 2019 20:32:06 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id CA54A20886FD1; Thu, 14 Feb 2019 12:32:06 -0800 (PST) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=134.134.136.20; helo=mga02.intel.com; envelope-from=dan.j.williams@intel.com; receiver=linux-nvdimm@lists.01.org Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id E43FA201B0442 for ; Thu, 14 Feb 2019 12:32:04 -0800 (PST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 14 Feb 2019 12:32:04 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.58,370,1544515200"; d="scan'208";a="116289937" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.16]) by orsmga006.jf.intel.com with ESMTP; 14 Feb 2019 12:32:04 -0800 Subject: [PATCH v2] nfit/ars: Allow root to busy-poll the ARS state machine From: Dan Williams To: linux-nvdimm@lists.01.org Date: Thu, 14 Feb 2019 12:19:26 -0800 Message-ID: <155017550946.954637.8586902409974005660.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <155017502147.944049.2893295352368862579.stgit@dwillia2-desk3.amr.corp.intel.com> References: <155017502147.944049.2893295352368862579.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.18-2-gc94f MIME-Version: 1.0 X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Erwin Tsaur , linux-kernel@vger.kernel.org Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP The ARS implementation implements exponential back-off on the poll interval to prevent high-frequency access to the DIMM / platform interface. Depending on when the ARS completes the poll interval may exceed the completion event by minutes. Allow root to reset the timeout each time it probes the status. A one-second timeout is still enforced, but root can otherwise can control the poll interval. Reported-by: Erwin Tsaur Signed-off-by: Dan Williams --- Change since v1: Use mod_delayed_work() instead of queue_delayed_work() to modify the timeout for existing work. drivers/acpi/nfit/core.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c index 934be96dc149..b1ab593a808a 100644 --- a/drivers/acpi/nfit/core.c +++ b/drivers/acpi/nfit/core.c @@ -1328,6 +1328,12 @@ static ssize_t scrub_show(struct device *dev, rc = sprintf(buf, "%d%s", acpi_desc->scrub_count, acpi_desc->scrub_busy && !acpi_desc->cancel ? "+\n" : "\n"); + /* Allow an admin to poll the busy state at a higher rate */ + if (acpi_desc->scrub_busy && !acpi_desc->cancel + && capable(CAP_SYS_RAWIO)) { + acpi_desc->scrub_tmo = 1; + mod_delayed_work(nfit_wq, &acpi_desc->dwork, HZ); + } mutex_unlock(&acpi_desc->init_mutex); } device_unlock(dev);